Use of Color:Understanding SC 1.4.1

1.4.1 Use of Color:
Color is not used as the only visual means of conveying information, indicating an action, prompting a response, or distinguishing a visual element.
(Level A)

Note: This success criterion addresses color perception specifically. Other forms of perception are covered in Guideline 1.3 including programmatic access to color and other visual presentation coding.

Intent of this Success Criterion

The intent of this Success Criterion is to ensure that all users can access information that is conveyed by color differences, that is, by the use of color where each color has a meaning assigned to it. If the information is conveyed through color differences in an image (or other non-text format), the color may not be seen by users with color deficiencies. In this case, providing the information conveyed with color through another visual means ensures users who cannot see color can still perceive the information.

Color is an important asset in design of Web content, enhancing its aesthetic appeal, its usability, and its accessibility. However, some users have difficulty perceiving color. People with partial sight often experience limited color vision, and many older users do not see color well. In addition, people using text-only, limited-color or monochrome displays and browsers will be unable to access information that is presented only in color.

Examples of information conveyed by color differences: “required fields are red", “error is shown in red", and “Mary's sales are in red, Tom's are in blue". Examples of indications of an action include: using color to indicate that a link will open in a new window or that a database entry has been updated successfully. An example of prompting a response would be: using highlighting on form fields to indicate that a required field had been left blank.

Note: This should not in any way discourage the use of color on a page, or even color coding if it is redundant with other visual indication.

Specific Benefits of Success Criterion 1.4.1:

Users with partial sight often experience limited color vision.

Some older users may not be able to see color well.

Users who have color-blindness benefit when information conveyed by color is available in other visual ways.

People using text-only, limited color, or monochrome displays may be unable to access color-dependent information.

Users who have problems distinguishing between colors can look or listen for text cues.

People using Braille displays or other tactile interfaces can detect text cues by touch.

Examples of Success Criterion 1.4.1

A form that uses color and text to indicate required fields

A form contains both required and optional fields. Instructions at the top of the form explain that required fields are labeled with red text and also with an icon whose text alternative says, "Required." Both the red text and the icon are programmatically associated with the appropriate form fields so that assistive technology users can determine the required fields.

An examination.

Students view an SVG image of a chemical compound and identify the chemical elements present based on the colors and numbers used in the diagram. The text alternatives associated with each element name the color of the element and indicate the element's position in the diagram. Students who cannot perceive color have the same information about the compound as their classmates. (This technique also satisfies Guideline 1.1 Level A.)

Disabled Form elements.

Form elements which are disabled via markup or scripting, are greyed out and made inactive by the user agent. When in the disabled state these elements do not receive focus. Assistive technologies can programmatically determine the state of disabled elements and will provide this information to the user as the elements are encountered on the page. The change in color and loss of focus provides redundant, visual information about the state of the control.

Techniques and Failures for Success Criterion 1.4.1 - Use of Color

Each numbered item in this section represents a technique or combination of techniques that the WCAG Working Group deems sufficient for meeting this Success Criterion. [begin change]However, it is not necessary to use these particular techniques. Any techniques, whether published by the WCAG group or not, can be sufficient if a) they satisfy the Success Criterion and b) all of the WCAG 2.0 conformance requirements have been met.[end change]

Sufficient Techniques

Instructions: Select the situation below that matches your content. Each situation includes techniques or combinations of techniques that are known and documented to be sufficient for that situation.

Situation A: If the color of particular words, backgrounds, or other content is used to indicate information:

Situation B: If color is used within an image to convey information:

Additional Techniques (Advisory) for 1.4.1

Although not required for conformance, the following additional techniques should be considered in order to make content more accessible. Not all techniques can be used or would be effective in all situations.